Regeneration of a glycol fluid used for dehydration of gas

摘要

In a new process for the regeneration of a liquid of the glycol family (defined as ethylene glycol, diethylene glycol, triethylene glycol or tetraethylene glycol) used in the dehydration of a gas (particularly natural gas), the glycol is subjected to a pre-dehydration stage by atmospheric distillation (7) and the residue from this stage is passed to stage of expansion under vacuum. The vapour phase from the expansion stage (11) is mixed with the glycol charge to be re-generated upstream (6) of the distillation stage (7). The glycol-rich liquid phase from (11) is evacuated by gravity to a storage reservoir (14) at a lower level. The vapours from the atmospheric distillation are partially condensed in (25). The condensate is separated into a light phase containing the hydrocarbons (particularly aromatics) and a heavy phase which is partially recycled to the distillation stage to provide external reflux. The glycol is regenerated to a high concentration, greater or equal to the concentration obtained at atmospheric pressure and at the limiting temperature of thermal degradation, with a reboiler bath temperature (8) less than the thermal degradation temperature.